Energy absorbing characteristics of the composite contoured-core sandwich panels

It is a challenging task to reduce the weight and manufacturing cost of a lightweight energy absorbing structure, while at the same time to maintain a reasonable strength and structural performance. This paper investigates the energy absorbing characteristics of the sandwich panels based on spherical-roof and flat-roof composite contoured cores subjected to quasi-static loading. Initial attention was focused on establishing the influence of the core profile and core cell wall thickness on the energy absorbing characteristics of both glass fibre reinforced plastic (GFRP) and carbon fibre reinforced plastic (CFRP) panels. It has been shown that the specific energy absorption capacity of the panel increases nonlinearly with increasing core cell wall thickness, with the spherical-roof cores outperforming their flat-roof counterparts. The results of these tests were compared with previously published data on a range of the relevant core structures, where it has been shown that the energy absorbing characteristics of the current spherical-roof system are superior to other core structures, such as aluminium and composite egg-box structures. Finally, a finite element analysis was undertaken to predict the crushing behaviour, energy absorbing characteristics and the failure modes of these core materials in reasonably good correlation with the corresponding test results.